I've used the ffmpeg cli app to generate a set of user guide videos for a web app, and scripted it so that they can easily be recreated with client's logos and color schemes for overlays. This would be an alternative product for doing that.

they have a section [1] explaining their reasoning

Create a slideshow from a set of pictures with text overlay

Create a fast paced trailer or promo video

Create a tutorial video with help text

Simply convert a video to a GIF

Resize video to any size or framerate and with automatic letterbox/crop (e.g. if you need to upload a video somewhere but the site complains Video must be 1337x1000 30fps)

[1] https://github.com/mifi/editly#use-cases

Use your imagination.

Edit: For a group of people that have critical thinking skills it's discouraging to see the same trite questions asked over and over again. The author of the project does not have to sell a use case. Use your imagination to create one. George Boole did not pitch the transistor.